Add type cast definitions for CPDF_Stream.

This Cl adds ToStream, CPDF_Object::AsStream and CPDF_Object::IsStream and
updates the src to use them as needed.

BUG=pdfium:201
R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1402413004 .

27 files changed, 312 insertions, 362 deletions

diff --git a/core/include/fpdfapi/fpdf_objects.h b/core/include/fpdfapi/fpdf_objects.h
index 162a514cd7..45ca665b99 100644
--- a/core/include/fpdfapi/fpdf_objects.h
+++ b/core/include/fpdfapi/fpdf_objects.h
@@ -84,6 +84,7 @@ class CPDF_Object {
   bool IsDictionary() const { return m_Type == PDFOBJ_DICTIONARY; }
   bool IsName() const { return m_Type == PDFOBJ_NAME; }
   bool IsNumber() const { return m_Type == PDFOBJ_NUMBER; }
+  bool IsStream() const { return m_Type == PDFOBJ_STREAM; }
   bool IsString() const { return m_Type == PDFOBJ_STRING; }
 
   CPDF_Array* AsArray();
@@ -101,6 +102,9 @@ class CPDF_Object {
   CPDF_Number* AsNumber();
   const CPDF_Number* AsNumber() const;
 
+  CPDF_Stream* AsStream();
+  const CPDF_Stream* AsStream() const;
+
   CPDF_String* AsString();
   const CPDF_String* AsString() const;
 
@@ -519,6 +523,13 @@ class CPDF_Stream : public CPDF_Object {
   friend class CPDF_StreamAcc;
   friend class CPDF_AttachmentAcc;
 };
+inline CPDF_Stream* ToStream(CPDF_Object* obj) {
+  return obj ? obj->AsStream() : nullptr;
+}
+inline const CPDF_Stream* ToStream(const CPDF_Object* obj) {
+  return obj ? obj->AsStream() : nullptr;
+}
+
 class CPDF_StreamAcc {
  public:
   CPDF_StreamAcc();
diff --git a/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp b/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
index 32802d0001..383284e6f9 100644
--- a/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
+++ b/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
@@ -131,12 +131,13 @@ void CPDF_PageContentGenerate::TransformContent(CFX_Matrix& matrix) {
     int i = 0;
     for (i = 0; i < iCount; ++i) {
       pContent = pArray->GetElement(i);
-      if (!pContent || pContent->GetType() != PDFOBJ_STREAM) {
+      CPDF_Stream* pStream = ToStream(pContent);
+      if (!pStream)
         continue;
-      }
-      CPDF_StreamAcc* pStream = new CPDF_StreamAcc();
-      pStream->LoadAllData((CPDF_Stream*)pContent);
-      pContentArray[i] = pStream;
+
+      CPDF_StreamAcc* pStreamAcc = new CPDF_StreamAcc();
+      pStreamAcc->LoadAllData(pStream);
+      pContentArray[i] = pStreamAcc;
       size += pContentArray[i]->GetSize() + 1;
     }
     int pos = 0;
@@ -151,9 +152,9 @@ void CPDF_PageContentGenerate::TransformContent(CFX_Matrix& matrix) {
     ProcessForm(buf, pBuf, size, matrix);
     FX_Free(pBuf);
     FX_Free(pContentArray);
-  } else if (pContent->GetType() == PDFOBJ_STREAM) {
+  } else if (CPDF_Stream* pStream = pContent->AsStream()) {
     CPDF_StreamAcc contentStream;
-    contentStream.LoadAllData((CPDF_Stream*)pContent);
+    contentStream.LoadAllData(pStream);
     ProcessForm(buf, contentStream.GetData(), contentStream.GetSize(), matrix);
   }
   CPDF_Stream* pStream = new CPDF_Stream(NULL, 0, NULL);
diff --git a/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp b/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
index d6522158f1..16124a3c38 100644
--- a/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
+++ b/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
@@ -146,7 +146,7 @@ int32_t PDF_CreatorAppendObject(const CPDF_Object* pObj,
       break;
     }
     case PDFOBJ_STREAM: {
-      CPDF_Stream* p = (CPDF_Stream*)pObj;
+      const CPDF_Stream* p = pObj->AsStream();
       if (PDF_CreatorAppendObject(p->GetDict(), pFile, offset) < 0) {
         return -1;
       }
@@ -929,9 +929,9 @@ static FX_BOOL _IsXRefNeedEnd(CPDF_XRefStream* pXRef, FX_DWORD flag) {
   return (iCount >= PDF_XREFSTREAM_MAXSIZE);
 }
 int32_t CPDF_Creator::WriteIndirectObjectToStream(const CPDF_Object* pObj) {
-  if (!m_pXRefStream) {
+  if (!m_pXRefStream)
     return 1;
-  }
+
   FX_DWORD objnum = pObj->GetObjNum();
   if (m_pParser && m_pParser->m_ObjVersion.GetSize() > (int32_t)objnum &&
       m_pParser->m_ObjVersion[objnum] > 0) {
@@ -942,36 +942,29 @@ int32_t CPDF_Creator::WriteIndirectObjectToStream(const CPDF_Object* pObj) {
     return 1;
 
   CPDF_Dictionary* pDict = pObj->GetDict();
-  if (pObj->GetType() == PDFOBJ_STREAM) {
-    if (pDict && pDict->GetString(FX_BSTRC("Type")) == FX_BSTRC("XRef")) {
+  if (pObj->IsStream())
+    if (pDict && pDict->GetString(FX_BSTRC("Type")) == FX_BSTRC("XRef"))
       return 0;
-    }
     return 1;
-  }
+
   if (pDict) {
-    if (pDict == m_pDocument->m_pRootDict || pDict == m_pEncryptDict) {
+    if (pDict == m_pDocument->m_pRootDict || pDict == m_pEncryptDict)
       return 1;
-    }
-    if (IsSignatureDict(pDict)) {
+    if (IsSignatureDict(pDict))
       return 1;
-    }
-    if (pDict->GetString(FX_BSTRC("Type")) == FX_BSTRC("Page")) {
+    if (pDict->GetString(FX_BSTRC("Type")) == FX_BSTRC("Page"))
       return 1;
-    }
   }
+
   m_pXRefStream->AddObjectNumberToIndexArray(objnum);
-  if (m_pXRefStream->CompressIndirectObject(objnum, pObj, this) < 0) {
+  if (m_pXRefStream->CompressIndirectObject(objnum, pObj, this) < 0)
     return -1;
-  }
-  if (!_IsXRefNeedEnd(m_pXRefStream, m_dwFlags)) {
+  if (!_IsXRefNeedEnd(m_pXRefStream, m_dwFlags))
     return 0;
-  }
-  if (!m_pXRefStream->End(this)) {
+  if (!m_pXRefStream->End(this))
     return -1;
-  }
-  if (!m_pXRefStream->Start()) {
+  if (!m_pXRefStream->Start())
     return -1;
-  }
   return 0;
 }
 int32_t CPDF_Creator::WriteIndirectObjectToStream(FX_DWORD objnum,
@@ -1017,7 +1010,7 @@ int32_t CPDF_Creator::WriteStream(const CPDF_Object* pStream,
                                   FX_DWORD objnum,
                                   CPDF_CryptoHandler* pCrypto) {
   CPDF_FlateEncoder encoder;
-  encoder.Initialize((CPDF_Stream*)pStream,
+  encoder.Initialize(const_cast<CPDF_Stream*>(pStream->AsStream()),
                      pStream == m_pMetadata ? FALSE : m_bCompress);
   CPDF_Encryptor encryptor;
   if (!encryptor.Initialize(pCrypto, objnum, encoder.m_pData,
@@ -1050,33 +1043,30 @@ int32_t CPDF_Creator::WriteStream(const CPDF_Object* pStream,
 int32_t CPDF_Creator::WriteIndirectObj(FX_DWORD objnum,
                                        const CPDF_Object* pObj) {
   int32_t len = m_File.AppendDWord(objnum);
-  if (len < 0) {
+  if (len < 0)
     return -1;
-  }
+
   m_Offset += len;
-  if ((len = m_File.AppendString(FX_BSTRC(" 0 obj\r\n"))) < 0) {
+  if ((len = m_File.AppendString(FX_BSTRC(" 0 obj\r\n"))) < 0)
     return -1;
-  }
+
   m_Offset += len;
-  if (pObj->GetType() == PDFOBJ_STREAM) {
-    CPDF_CryptoHandler* pHandler = NULL;
+  if (pObj->IsStream()) {
+    CPDF_CryptoHandler* pHandler = nullptr;
     pHandler =
         (pObj == m_pMetadata && !m_bEncryptMetadata) ? NULL : m_pCryptoHandler;
-    if (WriteStream(pObj, objnum, pHandler) < 0) {
+    if (WriteStream(pObj, objnum, pHandler) < 0)
       return -1;
-    }
   } else {
-    if (WriteDirectObj(objnum, pObj) < 0) {
+    if (WriteDirectObj(objnum, pObj) < 0)
       return -1;
-    }
   }
-  if ((len = m_File.AppendString(FX_BSTRC("\r\nendobj\r\n"))) < 0) {
+  if ((len = m_File.AppendString(FX_BSTRC("\r\nendobj\r\n"))) < 0)
     return -1;
-  }
+
   m_Offset += len;
-  if (AppendObjectNumberToXRef(objnum) < 0) {
+  if (AppendObjectNumberToXRef(objnum) < 0)
     return -1;
-  }
   return 0;
 }
 int32_t CPDF_Creator::WriteIndirectObj(const CPDF_Object* pObj) {
@@ -1139,7 +1129,8 @@ int32_t CPDF_Creator::WriteDirectObj(FX_DWORD objnum,
     }
     case PDFOBJ_STREAM: {
       CPDF_FlateEncoder encoder;
-      encoder.Initialize((CPDF_Stream*)pObj, m_bCompress);
+      encoder.Initialize(const_cast<CPDF_Stream*>(pObj->AsStream()),
+                         m_bCompress);
       CPDF_Encryptor encryptor;
       CPDF_CryptoHandler* pHandler = m_pCryptoHandler;
       encryptor.Initialize(pHandler, objnum, encoder.m_pData, encoder.m_dwSize);
diff --git a/core/src/fpdfapi/fpdf_font/fpdf_font.cpp b/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
index 9954efcc5d..543816b03a 100644
--- a/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
+++ b/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
@@ -119,7 +119,7 @@ CPDF_Font::~CPDF_Font() {
 
   if (m_pFontFile) {
     m_pDocument->GetPageData()->ReleaseFontFileStreamAcc(
-        (CPDF_Stream*)m_pFontFile->GetStream());
+        const_cast<CPDF_Stream*>(m_pFontFile->GetStream()->AsStream()));
   }
 }
 FX_BOOL CPDF_Font::IsVertWriting() const {
@@ -275,7 +275,7 @@ void CPDF_Font::LoadFontDescriptor(CPDF_Dictionary* pFontDesc) {
   FX_DWORD dwFontSize = m_pFontFile->GetSize();
   if (!m_Font.LoadEmbedded(pFontData, dwFontSize)) {
     m_pDocument->GetPageData()->ReleaseFontFileStreamAcc(
-        (CPDF_Stream*)m_pFontFile->GetStream());
+        const_cast<CPDF_Stream*>(m_pFontFile->GetStream()->AsStream()));
     m_pFontFile = nullptr;
   }
 }
@@ -1709,10 +1709,10 @@ void CPDF_Type3Font::CheckType3FontMetrics() {
   CheckFontMetrics();
 }
 CPDF_Type3Char* CPDF_Type3Font::LoadChar(FX_DWORD charcode, int level) {
-  if (level >= _FPDF_MAX_TYPE3_FORM_LEVEL_) {
-    return NULL;
-  }
-  CPDF_Type3Char* pChar = NULL;
+  if (level >= _FPDF_MAX_TYPE3_FORM_LEVEL_)
+    return nullptr;
+
+  CPDF_Type3Char* pChar = nullptr;
   if (m_CacheMap.Lookup((void*)(uintptr_t)charcode, (void*&)pChar)) {
     if (pChar->m_bPageRequired && m_pPageResources) {
       delete pChar;
@@ -1723,19 +1723,19 @@ CPDF_Type3Char* CPDF_Type3Font::LoadChar(FX_DWORD charcode, int level) {
   }
   const FX_CHAR* name =
       GetAdobeCharName(m_BaseEncoding, m_pCharNames, charcode);
-  if (name == NULL) {
-    return NULL;
-  }
+  if (!name)
+    return nullptr;
+
   CPDF_Stream* pStream =
-      (CPDF_Stream*)(m_pCharProcs ? m_pCharProcs->GetElementValue(name) : NULL);
-  if (pStream == NULL || pStream->GetType() != PDFOBJ_STREAM) {
-    return NULL;
-  }
+      ToStream(m_pCharProcs ? m_pCharProcs->GetElementValue(name) : nullptr);
+  if (!pStream)
+    return nullptr;
+
   pChar = new CPDF_Type3Char;
   pChar->m_pForm = new CPDF_Form(
       m_pDocument, m_pFontResources ? m_pFontResources : m_pPageResources,
-      pStream, NULL);
-  pChar->m_pForm->ParseContent(NULL, NULL, pChar, NULL, level + 1);
+      pStream, nullptr);
+  pChar->m_pForm->ParseContent(nullptr, nullptr, pChar, nullptr, level + 1);
   FX_FLOAT scale = m_FontMatrix.GetXUnit();
   pChar->m_Width = (int32_t)(pChar->m_Width * scale + 0.5f);
   FX_RECT& rcBBox = pChar->m_BBox;
@@ -1753,7 +1753,7 @@ CPDF_Type3Char* CPDF_Type3Font::LoadChar(FX_DWORD charcode, int level) {
   m_CacheMap.SetAt((void*)(uintptr_t)charcode, pChar);
   if (pChar->m_pForm->CountObjects() == 0) {
     delete pChar->m_pForm;
-    pChar->m_pForm = NULL;
+    pChar->m_pForm = nullptr;
   }
   return pChar;
 }
diff --git a/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp b/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
index 8972201b66..02f0933f36 100644
--- a/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
+++ b/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
@@ -1215,9 +1215,8 @@ FX_BOOL CPDF_CIDFont::_Load() {
             ->GetPageModule()
             ->GetFontGlobals()
             ->m_CMapManager.GetPredefinedCMap(cmap, m_pFontFile && m_bType1);
-  } else if (pEncoding->GetType() == PDFOBJ_STREAM) {
+  } else if (CPDF_Stream* pStream = pEncoding->AsStream()) {
     m_pAllocatedCMap = m_pCMap = new CPDF_CMap;
-    CPDF_Stream* pStream = (CPDF_Stream*)pEncoding;
     CPDF_StreamAcc acc;
     acc.LoadAllData(pStream, FALSE);
     m_pCMap->LoadEmbedded(acc.GetData(), acc.GetSize());
@@ -1265,9 +1264,9 @@ FX_BOOL CPDF_CIDFont::_Load() {
       CPDF_Object* pmap =
           pCIDFontDict->GetElementValue(FX_BSTRC("CIDToGIDMap"));
       if (pmap) {
-        if (pmap->GetType() == PDFOBJ_STREAM) {
+        if (CPDF_Stream* pStream = pmap->AsStream()) {
           m_pCIDToGIDMap = new CPDF_StreamAcc;
-          m_pCIDToGIDMap->LoadAllData((CPDF_Stream*)pmap, FALSE);
+          m_pCIDToGIDMap->LoadAllData(pStream, FALSE);
         } else if (pmap->GetString() == FX_BSTRC("Identity")) {
 #if _FXM_PLATFORM_ == _FXM_PLATFORM_APPLE_
           if (m_pFontFile) {
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
index 4f54c01ce7..bed3cfbb2c 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
@@ -913,9 +913,9 @@ FX_BOOL CPDF_IndexedCS::v_Load(CPDF_Document* pDoc, CPDF_Array* pArray) {
 
   if (CPDF_String* pString = pTableObj->AsString()) {
     m_Table = pString->GetString();
-  } else if (pTableObj->GetType() == PDFOBJ_STREAM) {
+  } else if (CPDF_Stream* pStream = pTableObj->AsStream()) {
     CPDF_StreamAcc acc;
-    acc.LoadAllData((CPDF_Stream*)pTableObj, FALSE);
+    acc.LoadAllData(pStream, FALSE);
     m_Table = CFX_ByteStringC(acc.GetData(), acc.GetSize());
   }
   return TRUE;
@@ -1204,8 +1204,8 @@ CPDF_ColorSpace* CPDF_ColorSpace::Load(CPDF_Document* pDoc, CPDF_Object* pObj) {
   if (pObj->IsName())
     return _CSFromName(pObj->GetString());
 
-  if (pObj->GetType() == PDFOBJ_STREAM) {
-    CPDF_Dictionary* pDict = ((CPDF_Stream*)pObj)->GetDict();
+  if (CPDF_Stream* pStream = pObj->AsStream()) {
+    CPDF_Dictionary* pDict = pStream->GetDict();
     if (!pDict)
       return nullptr;
 
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp
index 436cca6d99..8656b72023 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp
@@ -470,7 +470,7 @@ CPDF_Image* CPDF_DocPageData::GetImage(CPDF_Object* pImageStream) {
   }
 
   CPDF_Image* pImage = new CPDF_Image(m_pPDFDoc);
-  pImage->LoadImageF((CPDF_Stream*)pImageStream, FALSE);
+  pImage->LoadImageF(pImageStream->AsStream(), FALSE);
 
   CPDF_CountedImage* imageData = new CPDF_CountedImage(pImage);
   m_ImageMap[dwImageObjNum] = imageData;
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
index d66a9efdaa..2d35dd85be 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
@@ -491,10 +491,10 @@ CPDF_SampledFunc::~CPDF_SampledFunc() {
   FX_Free(m_pDecodeInfo);
 }
 FX_BOOL CPDF_SampledFunc::v_Init(CPDF_Object* pObj) {
-  if (pObj->GetType() != PDFOBJ_STREAM) {
-    return FALSE;
-  }
-  CPDF_Stream* pStream = (CPDF_Stream*)pObj;
+  CPDF_Stream* pStream = pObj->AsStream();
+  if (!pStream)
+    return false;
+
   CPDF_Dictionary* pDict = pStream->GetDict();
   CPDF_Array* pSize = pDict->GetArray(FX_BSTRC("Size"));
   CPDF_Array* pEncode = pDict->GetArray(FX_BSTRC("Encode"));
@@ -632,7 +632,7 @@ class CPDF_PSFunc : public CPDF_Function {
 };
 
 FX_BOOL CPDF_PSFunc::v_Init(CPDF_Object* pObj) {
-  CPDF_Stream* pStream = (CPDF_Stream*)pObj;
+  CPDF_Stream* pStream = pObj->AsStream();
   CPDF_StreamAcc acc;
   acc.LoadAllData(pStream, FALSE);
   return m_PS.Parse((const FX_CHAR*)acc.GetData(), acc.GetSize());
@@ -814,10 +814,8 @@ CPDF_Function* CPDF_Function::Load(CPDF_Object* pFuncObj) {
   }
   CPDF_Function* pFunc = NULL;
   int type;
-  if (pFuncObj->GetType() == PDFOBJ_STREAM) {
-    type = ((CPDF_Stream*)pFuncObj)
-               ->GetDict()
-               ->GetInteger(FX_BSTRC("FunctionType"));
+  if (CPDF_Stream* pStream = pFuncObj->AsStream()) {
+    type = pStream->GetDict()->GetInteger(FX_BSTRC("FunctionType"));
   } else if (CPDF_Dictionary* pDict = pFuncObj->AsDictionary()) {
     type = pDict->GetInteger(FX_BSTRC("FunctionType"));
   } else {
@@ -849,20 +847,17 @@ CPDF_Function::~CPDF_Function() {
   FX_Free(m_pRanges);
 }
 FX_BOOL CPDF_Function::Init(CPDF_Object* pObj) {
-  CPDF_Dictionary* pDict;
-  if (pObj->GetType() == PDFOBJ_STREAM) {
-    pDict = ((CPDF_Stream*)pObj)->GetDict();
-  } else {
-    pDict = pObj->AsDictionary();
-  }
+  CPDF_Stream* pStream = pObj->AsStream();
+  CPDF_Dictionary* pDict = pStream ? pStream->GetDict() : pObj->AsDictionary();
+
   CPDF_Array* pDomains = pDict->GetArray(FX_BSTRC("Domain"));
-  if (pDomains == NULL) {
+  if (!pDomains)
     return FALSE;
-  }
+
   m_nInputs = pDomains->GetCount() / 2;
-  if (m_nInputs == 0) {
+  if (m_nInputs == 0)
     return FALSE;
-  }
+
   m_pDomains = FX_Alloc2D(FX_FLOAT, m_nInputs, 2);
   for (int i = 0; i < m_nInputs * 2; i++) {
     m_pDomains[i] = pDomains->GetFloat(i);
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_image.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_image.cpp
index 9cdf00e717..a24da0adc1 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_image.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_image.cpp
@@ -45,15 +45,14 @@ void CPDF_Image::Release() {
   }
 }
 CPDF_Image* CPDF_Image::Clone() {
-  if (m_pStream->GetObjNum()) {
+  if (m_pStream->GetObjNum())
     return m_pDocument->GetPageData()->GetImage(m_pStream);
-  }
+
   CPDF_Image* pImage = new CPDF_Image(m_pDocument);
-  pImage->LoadImageF((CPDF_Stream*)((CPDF_Object*)m_pStream)->Clone(),
-                     m_bInline);
-  if (m_bInline) {
+  pImage->LoadImageF(ToStream(m_pStream->Clone()), m_bInline);
+  if (m_bInline)
     pImage->SetInlineDict(ToDictionary(m_pInlineDict->Clone(TRUE)));
-  }
+
   return pImage;
 }
 CPDF_Image::CPDF_Image(CPDF_Document* pDoc) {
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
index 7aa2cf8aa3..3295b7f9e0 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
@@ -716,12 +716,12 @@ void CPDF_StreamContentParser::Handle_ExecuteXObject() {
       return;
     }
   }
-  CPDF_Stream* pXObject =
-      (CPDF_Stream*)FindResourceObj(FX_BSTRC("XObject"), name);
-  if (pXObject == NULL || pXObject->GetType() != PDFOBJ_STREAM) {
+  CPDF_Stream* pXObject = ToStream(FindResourceObj(FX_BSTRC("XObject"), name));
+  if (!pXObject) {
     m_bResourceMissing = TRUE;
     return;
   }
+
   CFX_ByteStringC type =
       pXObject->GetDict()
           ? pXObject->GetDict()->GetConstString(FX_BSTRC("Subtype"))
@@ -1151,7 +1151,7 @@ void CPDF_StreamContentParser::Handle_ShadeFill() {
     bbox = m_BBox;
   }
   if (pShading->m_ShadingType >= 4) {
-    bbox.Intersect(_GetShadingBBox((CPDF_Stream*)pShading->m_pShadingObj,
+    bbox.Intersect(_GetShadingBBox(ToStream(pShading->m_pShadingObj),
                                    pShading->m_ShadingType, &pObj->m_Matrix,
                                    pShading->m_pFunctions, pShading->m_nFuncs,
                                    pShading->m_pCS));
@@ -1262,8 +1262,7 @@ CPDF_Pattern* CPDF_StreamContentParser::FindPattern(const CFX_ByteString& name,
                                                     FX_BOOL bShading) {
   CPDF_Object* pPattern = FindResourceObj(
       bShading ? FX_BSTRC("Shading") : FX_BSTRC("Pattern"), name);
-  if (pPattern == NULL ||
-      (!pPattern->IsDictionary() && pPattern->GetType() != PDFOBJ_STREAM)) {
+  if (!pPattern || (!pPattern->IsDictionary() && !pPattern->IsStream())) {
     m_bResourceMissing = TRUE;
     return NULL;
   }
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
index c27ede44cb..b86d00851c 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
@@ -960,10 +960,10 @@ void CPDF_ContentParser::Start(CPDF_Page* pPage, CPDF_ParseOptions* pOptions) {
     m_Status = Done;
     return;
   }
-  if (pContent->GetType() == PDFOBJ_STREAM) {
+  if (CPDF_Stream* pStream = pContent->AsStream()) {
     m_nStreams = 0;
     m_pSingleStream = new CPDF_StreamAcc;
-    m_pSingleStream->LoadAllData((CPDF_Stream*)pContent, FALSE);
+    m_pSingleStream->LoadAllData(pStream, FALSE);
   } else if (CPDF_Array* pArray = pContent->AsArray()) {
     m_nStreams = pArray->GetCount();
     if (m_nStreams == 0) {
@@ -1078,9 +1078,8 @@ void CPDF_ContentParser::Continue(IFX_Pause* pPause) {
         CPDF_Array* pContent =
             m_pObjects->m_pFormDict->GetArray(FX_BSTRC("Contents"));
         m_pStreamArray[m_CurrentOffset] = new CPDF_StreamAcc;
-        CPDF_Stream* pStreamObj =
-            (CPDF_Stream*)(pContent ? pContent->GetElementValue(m_CurrentOffset)
-                                    : NULL);
+        CPDF_Stream* pStreamObj = ToStream(
+            pContent ? pContent->GetElementValue(m_CurrentOffset) : nullptr);
         m_pStreamArray[m_CurrentOffset]->LoadAllData(pStreamObj, FALSE);
         m_CurrentOffset++;
       }
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
index a73bdc9e8e..7b04d8cd33 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
@@ -38,20 +38,21 @@ CPDF_TilingPattern::~CPDF_TilingPattern() {
   m_pForm = NULL;
 }
 FX_BOOL CPDF_TilingPattern::Load() {
-  if (m_pForm != NULL) {
+  if (m_pForm)
     return TRUE;
-  }
+
   CPDF_Dictionary* pDict = m_pPatternObj->GetDict();
-  if (pDict == NULL) {
+  if (!pDict)
     return FALSE;
-  }
+
   m_bColored = pDict->GetInteger(FX_BSTRC("PaintType")) == 1;
   m_XStep = (FX_FLOAT)FXSYS_fabs(pDict->GetNumber(FX_BSTRC("XStep")));
   m_YStep = (FX_FLOAT)FXSYS_fabs(pDict->GetNumber(FX_BSTRC("YStep")));
-  if (m_pPatternObj->GetType() != PDFOBJ_STREAM) {
+
+  CPDF_Stream* pStream = m_pPatternObj->AsStream();
+  if (!pStream)
     return FALSE;
-  }
-  CPDF_Stream* pStream = (CPDF_Stream*)m_pPatternObj;
+
   m_pForm = new CPDF_Form(m_pDocument, NULL, pStream);
   m_pForm->ParseContent(NULL, &m_ParentMatrix, NULL, NULL);
   m_BBox = pDict->GetRect(FX_BSTRC("BBox"));
@@ -253,14 +254,13 @@ CFX_FloatRect _GetShadingBBox(CPDF_Stream* pStream,
                               CPDF_Function** pFuncs,
                               int nFuncs,
                               CPDF_ColorSpace* pCS) {
-  if (pStream == NULL || pStream->GetType() != PDFOBJ_STREAM ||
-      pFuncs == NULL || pCS == NULL) {
+  if (!pStream || !pStream->IsStream() || !pFuncs || !pCS)
     return CFX_FloatRect(0, 0, 0, 0);
-  }
+
   CPDF_MeshStream stream;
-  if (!stream.Load(pStream, pFuncs, nFuncs, pCS)) {
+  if (!stream.Load(pStream, pFuncs, nFuncs, pCS))
     return CFX_FloatRect(0, 0, 0, 0);
-  }
+
   CFX_FloatRect rect;
   FX_BOOL bStarted = FALSE;
   FX_BOOL bGouraud = type == 4 || type == 5;
@@ -288,9 +288,8 @@ CFX_FloatRect _GetShadingBBox(CPDF_Stream* pStream,
     }
     stream.m_BitStream.SkipBits(stream.m_nComps * stream.m_nCompBits *
                                 color_count);
-    if (bGouraud) {
+    if (bGouraud)
       stream.m_BitStream.ByteAlign();
-    }
   }
   rect.Transform(pMatrix);
   return rect;
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_document.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_document.cpp
index 2396261276..5333fe8087 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_document.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_document.cpp
@@ -338,8 +338,9 @@ FX_BOOL CPDF_Document::IsFormStream(FX_DWORD objnum, FX_BOOL& bForm) const {
   {
     CPDF_Object* pObj;
     if (m_IndirectObjs.Lookup((void*)(uintptr_t)objnum, (void*&)pObj)) {
-      bForm = pObj->GetType() == PDFOBJ_STREAM &&
-              ((CPDF_Stream*)pObj)->GetDict()->GetString(FX_BSTRC("Subtype")) ==
+      CPDF_Stream* pStream = pObj->AsStream();
+      bForm = pStream &&
+              pStream->GetDict()->GetString(FX_BSTRC("Subtype")) ==
                   FX_BSTRC("Form");
       return TRUE;
     }
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
index 6a090ce64d..fc473319fc 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
@@ -31,7 +31,7 @@ void CPDF_Object::Destroy() {
       delete AsDictionary();
       break;
     case PDFOBJ_STREAM:
-      delete (CPDF_Stream*)this;
+      delete AsStream();
       break;
     default:
       delete this;
@@ -144,7 +144,7 @@ CPDF_Dictionary* CPDF_Object::GetDict() const {
       // See bug #234.
       return const_cast<CPDF_Dictionary*>(AsDictionary());
     case PDFOBJ_STREAM:
-      return ((CPDF_Stream*)this)->GetDict();
+      return AsStream()->GetDict();
     case PDFOBJ_REFERENCE: {
       CPDF_Reference* pRef = (CPDF_Reference*)this;
       CPDF_IndirectObjects* pIndirect = pRef->GetObjList();
@@ -222,7 +222,7 @@ FX_BOOL CPDF_Object::IsIdentical(CPDF_Object* pOther) const {
     case PDFOBJ_NULL:
       return TRUE;
     case PDFOBJ_STREAM:
-      return (((CPDF_Stream*)this)->Identical((CPDF_Stream*)pOther));
+      return AsStream()->Identical(pOther->AsStream());
     case PDFOBJ_REFERENCE:
       return (((CPDF_Reference*)this)->Identical((CPDF_Reference*)pOther));
   }
@@ -284,7 +284,7 @@ CPDF_Object* CPDF_Object::CloneInternal(FX_BOOL bDirect,
       return new CPDF_Null;
     }
     case PDFOBJ_STREAM: {
-      CPDF_Stream* pThis = (CPDF_Stream*)this;
+      const CPDF_Stream* pThis = AsStream();
       CPDF_StreamAcc acc;
       acc.LoadAllData(pThis, TRUE);
       FX_DWORD streamSize = acc.GetSize();
@@ -319,9 +319,9 @@ CFX_WideString CPDF_Object::GetUnicodeText(CFX_CharMap* pCharMap) const {
   if (const CPDF_String* pString = AsString())
     return PDF_DecodeText(pString->m_String, pCharMap);
 
-  if (m_Type == PDFOBJ_STREAM) {
+  if (const CPDF_Stream* pStream = AsStream()) {
     CPDF_StreamAcc stream;
-    stream.LoadAllData((CPDF_Stream*)this, FALSE);
+    stream.LoadAllData(pStream, FALSE);
     CFX_WideString result =
         PDF_DecodeText(stream.GetData(), stream.GetSize(), pCharMap);
     return result;
@@ -333,10 +333,10 @@ CFX_WideString CPDF_Object::GetUnicodeText(CFX_CharMap* pCharMap) const {
 void CPDF_Object::SetUnicodeText(const FX_WCHAR* pUnicodes, int len) {
   if (CPDF_String* pString = AsString()) {
     pString->m_String = PDF_EncodeText(pUnicodes, len);
-  } else if (m_Type == PDFOBJ_STREAM) {
+  } else if (CPDF_Stream* pStream = AsStream()) {
     CFX_ByteString result = PDF_EncodeText(pUnicodes, len);
-    ((CPDF_Stream*)this)
-        ->SetData((uint8_t*)result.c_str(), result.GetLength(), FALSE, FALSE);
+    pStream->SetData((uint8_t*)result.c_str(), result.GetLength(), FALSE,
+                     FALSE);
   }
 }
 
@@ -380,6 +380,14 @@ const CPDF_Number* CPDF_Object::AsNumber() const {
   return IsNumber() ? static_cast<const CPDF_Number*>(this) : nullptr;
 }
 
+CPDF_Stream* CPDF_Object::AsStream() {
+  return IsStream() ? static_cast<CPDF_Stream*>(this) : nullptr;
+}
+
+const CPDF_Stream* CPDF_Object::AsStream() const {
+  return IsStream() ? static_cast<const CPDF_Stream*>(this) : nullptr;
+}
+
 CPDF_String* CPDF_Object::AsString() {
   return IsString() ? static_cast<CPDF_String*>(this) : nullptr;
 }
@@ -487,23 +495,16 @@ FX_FLOAT CPDF_Array::GetNumber(FX_DWORD i) const {
 }
 CPDF_Dictionary* CPDF_Array::GetDict(FX_DWORD i) const {
   CPDF_Object* p = GetElementValue(i);
-  if (!p) {
+  if (!p)
     return NULL;
-  }
-  if (CPDF_Dictionary* pDict = p->AsDictionary()) {
+  if (CPDF_Dictionary* pDict = p->AsDictionary())
     return pDict;
-  }
-  if (p->GetType() == PDFOBJ_STREAM) {
-    return ((CPDF_Stream*)p)->GetDict();
-  }
+  if (CPDF_Stream* pStream = p->AsStream())
+    return pStream->GetDict();
   return NULL;
 }
 CPDF_Stream* CPDF_Array::GetStream(FX_DWORD i) const {
-  CPDF_Object* p = GetElementValue(i);
-  if (p == NULL || p->GetType() != PDFOBJ_STREAM) {
-    return NULL;
-  }
-  return (CPDF_Stream*)p;
+  return ToStream(GetElementValue(i));
 }
 CPDF_Array* CPDF_Array::GetArray(FX_DWORD i) const {
   return ToArray(GetElementValue(i));
@@ -703,26 +704,19 @@ FX_BOOL CPDF_Dictionary::GetBoolean(const CFX_ByteStringC& key,
 }
 CPDF_Dictionary* CPDF_Dictionary::GetDict(const CFX_ByteStringC& key) const {
   CPDF_Object* p = GetElementValue(key);
-  if (!p) {
+  if (!p)
     return nullptr;
-  }
-  if (CPDF_Dictionary* pDict = p->AsDictionary()) {
+  if (CPDF_Dictionary* pDict = p->AsDictionary())
     return pDict;
-  }
-  if (p->GetType() == PDFOBJ_STREAM) {
-    return ((CPDF_Stream*)p)->GetDict();
-  }
+  if (CPDF_Stream* pStream = p->AsStream())
+    return pStream->GetDict();
   return nullptr;
 }
 CPDF_Array* CPDF_Dictionary::GetArray(const CFX_ByteStringC& key) const {
   return ToArray(GetElementValue(key));
 }
 CPDF_Stream* CPDF_Dictionary::GetStream(const CFX_ByteStringC& key) const {
-  CPDF_Object* p = GetElementValue(key);
-  if (p == NULL || p->GetType() != PDFOBJ_STREAM) {
-    return NULL;
-  }
-  return (CPDF_Stream*)p;
+  return ToStream(GetElementValue(key));
 }
 CFX_FloatRect CPDF_Dictionary::GetRect(const CFX_ByteStringC& key) const {
   CFX_FloatRect rect;
@@ -1035,9 +1029,9 @@ void CPDF_StreamAcc::LoadAllData(const CPDF_Stream* pStream,
                                  FX_BOOL bRawAccess,
                                  FX_DWORD estimated_size,
                                  FX_BOOL bImageAcc) {
-  if (pStream == NULL || pStream->GetType() != PDFOBJ_STREAM) {
+  if (!pStream)
     return;
-  }
+
   m_pStream = pStream;
   if (pStream->IsMemoryBased() &&
       (!pStream->GetDict()->KeyExist(FX_BSTRC("Filter")) || bRawAccess)) {
@@ -1047,14 +1041,13 @@ void CPDF_StreamAcc::LoadAllData(const CPDF_Stream* pStream,
   }
   uint8_t* pSrcData;
   FX_DWORD dwSrcSize = pStream->m_dwSize;
-  if (dwSrcSize == 0) {
+  if (dwSrcSize == 0)
     return;
-  }
+
   if (!pStream->IsMemoryBased()) {
     pSrcData = m_pSrcData = FX_Alloc(uint8_t, dwSrcSize);
-    if (!pStream->ReadRawData(0, pSrcData, dwSrcSize)) {
+    if (!pStream->ReadRawData(0, pSrcData, dwSrcSize))
       return;
-    }
   } else {
     pSrcData = pStream->m_pDataBuf;
   }
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
index 8b822a8b9c..12e2a3946c 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
@@ -784,29 +784,20 @@ FX_BOOL CPDF_Parser::RebuildCrossRef() {
                 FX_FILESIZE obj_end = 0;
                 CPDF_Object* pObject = ParseIndirectObjectAtByStrict(
                     m_pDocument, obj_pos, objnum, NULL, &obj_end);
-                if (pObject) {
-                  int iType = pObject->GetType();
-                  if (iType == PDFOBJ_STREAM) {
-                    CPDF_Stream* pStream = (CPDF_Stream*)pObject;
-                    CPDF_Dictionary* pDict = pStream->GetDict();
-                    if (pDict) {
-                      if (pDict->KeyExist(FX_BSTRC("Type"))) {
-                        CFX_ByteString bsValue =
-                            pDict->GetString(FX_BSTRC("Type"));
-                        if (bsValue == FX_BSTRC("XRef") &&
-                            pDict->KeyExist(FX_BSTRC("Size"))) {
-                          CPDF_Object* pRoot =
-                              pDict->GetElement(FX_BSTRC("Root"));
-                          if (pRoot && pRoot->GetDict() &&
-                              pRoot->GetDict()->GetElement(FX_BSTRC("Pages"))) {
-                            if (m_pTrailer) {
-                              m_pTrailer->Release();
-                            }
-                            m_pTrailer = ToDictionary(pDict->Clone());
-                          }
+                if (CPDF_Stream* pStream = ToStream(pObject)) {
+                  if (CPDF_Dictionary* pDict = pStream->GetDict()) {
+                    if ((pDict->KeyExist(FX_BSTRC("Type"))) &&
+                        (pDict->GetString(FX_BSTRC("Type")) ==
+                             FX_BSTRC("XRef") &&
+                         pDict->KeyExist(FX_BSTRC("Size")))) {
+                      CPDF_Object* pRoot = pDict->GetElement(FX_BSTRC("Root"));
+                      if (pRoot && pRoot->GetDict() &&
+                          pRoot->GetDict()->GetElement(FX_BSTRC("Pages"))) {
+                        if (m_pTrailer)
+                          m_pTrailer->Release();
+                        m_pTrailer = ToDictionary(pDict->Clone());
                         }
                       }
-                    }
                   }
                 }
                 FX_FILESIZE offset = 0;
@@ -855,16 +846,12 @@ FX_BOOL CPDF_Parser::RebuildCrossRef() {
               m_Syntax.RestorePos(pos + i - m_Syntax.m_HeaderOffset);
               CPDF_Object* pObj = m_Syntax.GetObject(m_pDocument, 0, 0, 0);
               if (pObj) {
-                if (!pObj->IsDictionary() && pObj->GetType() != PDFOBJ_STREAM) {
+                if (!pObj->IsDictionary() && !pObj->AsStream()) {
                   pObj->Release();
                 } else {
-                  CPDF_Dictionary* pTrailer = NULL;
-                  if (pObj->GetType() == PDFOBJ_STREAM) {
-                    pTrailer = ((CPDF_Stream*)pObj)->GetDict();
-                  } else {
-                    pTrailer = pObj->AsDictionary();
-                  }
-                  if (pTrailer) {
+                  CPDF_Stream* pStream = pObj->AsStream();
+                  if (CPDF_Dictionary* pTrailer =
+                          pStream ? pStream->GetDict() : pObj->AsDictionary()) {
                     if (m_pTrailer) {
                       CPDF_Object* pRoot =
                           pTrailer->GetElement(FX_BSTRC("Root"));
@@ -886,7 +873,7 @@ FX_BOOL CPDF_Parser::RebuildCrossRef() {
                         pObj->Release();
                       }
                     } else {
-                      if (pObj->GetType() == PDFOBJ_STREAM) {
+                      if (pObj->IsStream()) {
                         m_pTrailer = ToDictionary(pTrailer->Clone());
                         pObj->Release();
                       } else {
@@ -1005,25 +992,25 @@ FX_BOOL CPDF_Parser::RebuildCrossRef() {
 FX_BOOL CPDF_Parser::LoadCrossRefV5(FX_FILESIZE pos,
                                     FX_FILESIZE& prev,
                                     FX_BOOL bMainXRef) {
-  CPDF_Stream* pStream =
-      (CPDF_Stream*)ParseIndirectObjectAt(m_pDocument, pos, 0, NULL);
-  if (!pStream) {
+  CPDF_Object* pObject = ParseIndirectObjectAt(m_pDocument, pos, 0, nullptr);
+  if (!pObject)
     return FALSE;
-  }
+
   if (m_pDocument) {
     CPDF_Dictionary* pDict = m_pDocument->GetRoot();
-    if (!pDict || pDict->GetObjNum() != pStream->m_ObjNum) {
-      m_pDocument->InsertIndirectObject(pStream->m_ObjNum, pStream);
+    if (!pDict || pDict->GetObjNum() != pObject->m_ObjNum) {
+      m_pDocument->InsertIndirectObject(pObject->m_ObjNum, pObject);
     } else {
-      if (pStream->GetType() == PDFOBJ_STREAM) {
-        pStream->Release();
-      }
+      if (pObject->IsStream())
+        pObject->Release();
       return FALSE;
     }
   }
-  if (pStream->GetType() != PDFOBJ_STREAM) {
+
+  CPDF_Stream* pStream = pObject->AsStream();
+  if (!pStream)
     return FALSE;
-  }
+
   prev = pStream->GetDict()->GetInteger(FX_BSTRC("Prev"));
   int32_t size = pStream->GetDict()->GetInteger(FX_BSTRC("Size"));
   if (size < 0) {
@@ -1245,15 +1232,15 @@ CPDF_Object* CPDF_Parser::ParseIndirectObject(CPDF_IndirectObjects* pObjList,
 }
 
 CPDF_StreamAcc* CPDF_Parser::GetObjectStream(FX_DWORD objnum) {
-  CPDF_StreamAcc* pStreamAcc = NULL;
-  if (m_ObjectStreamMap.Lookup((void*)(uintptr_t)objnum, (void*&)pStreamAcc)) {
+  CPDF_StreamAcc* pStreamAcc = nullptr;
+  if (m_ObjectStreamMap.Lookup((void*)(uintptr_t)objnum, (void*&)pStreamAcc))
     return pStreamAcc;
-  }
+
   const CPDF_Stream* pStream =
-      m_pDocument ? (CPDF_Stream*)m_pDocument->GetIndirectObject(objnum) : NULL;
-  if (pStream == NULL || pStream->GetType() != PDFOBJ_STREAM) {
-    return NULL;
-  }
+      ToStream(m_pDocument ? m_pDocument->GetIndirectObject(objnum) : nullptr);
+  if (!pStream)
+    return nullptr;
+
   pStreamAcc = new CPDF_StreamAcc;
   pStreamAcc->LoadAllData(pStream);
   m_ObjectStreamMap.SetAt((void*)(uintptr_t)objnum, pStreamAcc);
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
index a2d65fa4bd..606bd0f569 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
@@ -417,7 +417,7 @@ CFX_ByteTextBuf& operator<<(CFX_ByteTextBuf& buf, const CPDF_Object* pObj) {
       break;
     }
     case PDFOBJ_STREAM: {
-      CPDF_Stream* p = (CPDF_Stream*)pObj;
+      const CPDF_Stream* p = pObj->AsStream();
       buf << p->GetDict() << FX_BSTRC("stream\r\n");
       CPDF_StreamAcc acc;
       acc.LoadAllData(p, TRUE);
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
index 2754223f3e..0acaeba14c 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
@@ -1055,10 +1055,9 @@ CFX_DIBitmap* CPDF_RenderStatus::LoadSMask(CPDF_Dictionary* pSMaskDict,
   }
   CPDF_Function* pFunc = NULL;
   CPDF_Object* pFuncObj = pSMaskDict->GetElementValue(FX_BSTRC("TR"));
-  if (pFuncObj &&
-      (pFuncObj->IsDictionary() || pFuncObj->GetType() == PDFOBJ_STREAM)) {
+  if (pFuncObj && (pFuncObj->IsDictionary() || pFuncObj->IsStream()))
     pFunc = CPDF_Function::Load(pFuncObj);
-  }
+
   CFX_AffineMatrix matrix = *pMatrix;
   matrix.TranslateI(-pClipRect->left, -pClipRect->top);
   CPDF_Form form(m_pContext->m_pDocument, m_pContext->m_pPageResources, pGroup);
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
index fecd6da9b2..6af3ab4ce6 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
@@ -765,7 +765,7 @@ CPDF_DIBSource* CPDF_DIBSource::LoadMask(FX_DWORD& MatteColor) {
   CPDF_Stream* pSoftMask = m_pDict->GetStream(FX_BSTRC("SMask"));
   if (pSoftMask) {
     CPDF_Array* pMatte = pSoftMask->GetDict()->GetArray(FX_BSTRC("Matte"));
-    if (pMatte != NULL && m_pColorSpace &&
+    if (pMatte && m_pColorSpace &&
         (FX_DWORD)m_pColorSpace->CountComponents() <= m_nComponents) {
       FX_FLOAT* pColor = FX_Alloc(FX_FLOAT, m_nComponents);
       for (FX_DWORD i = 0; i < m_nComponents; i++) {
@@ -779,14 +779,12 @@ CPDF_DIBSource* CPDF_DIBSource::LoadMask(FX_DWORD& MatteColor) {
     }
     return LoadMaskDIB(pSoftMask);
   }
-  CPDF_Object* pMask = m_pDict->GetElementValue(FX_BSTRC("Mask"));
-  if (pMask == NULL) {
-    return NULL;
-  }
-  if (pMask->GetType() == PDFOBJ_STREAM) {
-    return LoadMaskDIB((CPDF_Stream*)pMask);
-  }
-  return NULL;
+
+  if (CPDF_Stream* pStream =
+          ToStream(m_pDict->GetElementValue(FX_BSTRC("Mask"))))
+    return LoadMaskDIB(pStream);
+
+  return nullptr;
 }
 int CPDF_DIBSource::StratLoadMask() {
   m_MatteColor = 0XFFFFFFFF;
@@ -807,14 +805,9 @@ int CPDF_DIBSource::StratLoadMask() {
     }
     return StartLoadMaskDIB();
   }
-  m_pMaskStream = m_pDict->GetElementValue(FX_BSTRC("Mask"));
-  if (m_pMaskStream == NULL) {
-    return 1;
-  }
-  if (m_pMaskStream->GetType() == PDFOBJ_STREAM) {
-    return StartLoadMaskDIB();
-  }
-  return 1;
+
+  m_pMaskStream = ToStream(m_pDict->GetElementValue(FX_BSTRC("Mask")));
+  return m_pMaskStream ? StartLoadMaskDIB() : 1;
 }
 int CPDF_DIBSource::ContinueLoadMaskDIB(IFX_Pause* pPause) {
   if (m_pMask == NULL) {
@@ -849,17 +842,16 @@ CPDF_DIBSource* CPDF_DIBSource::LoadMaskDIB(CPDF_Stream* pMask) {
 }
 int CPDF_DIBSource::StartLoadMaskDIB() {
   m_pMask = new CPDF_DIBSource;
-  int ret = m_pMask->StartLoadDIBSource(
-      m_pDocument, (CPDF_Stream*)m_pMaskStream, FALSE, NULL, NULL, TRUE);
+  int ret = m_pMask->StartLoadDIBSource(m_pDocument, m_pMaskStream, FALSE,
+                                        nullptr, nullptr, TRUE);
   if (ret == 2) {
-    if (m_Status == 0) {
+    if (m_Status == 0)
       m_Status = 2;
-    }
     return 2;
   }
   if (!ret) {
     delete m_pMask;
-    m_pMask = NULL;
+    m_pMask = nullptr;
     return 1;
   }
   return 1;
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_pattern.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_pattern.cpp
index b64002c13e..4ed6c07675 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_pattern.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_pattern.cpp
@@ -10,13 +10,13 @@
 #include "../fpdf_page/pageint.h"
 #include "render_int.h"
 #define SHADING_STEPS 256
-static void _DrawAxialShading(CFX_DIBitmap* pBitmap,
-                              CFX_AffineMatrix* pObject2Bitmap,
-                              CPDF_Dictionary* pDict,
-                              CPDF_Function** pFuncs,
-                              int nFuncs,
-                              CPDF_ColorSpace* pCS,
-                              int alpha) {
+static void DrawAxialShading(CFX_DIBitmap* pBitmap,
+                             CFX_AffineMatrix* pObject2Bitmap,
+                             CPDF_Dictionary* pDict,
+                             CPDF_Function** pFuncs,
+                             int nFuncs,
+                             CPDF_ColorSpace* pCS,
+                             int alpha) {
   ASSERT(pBitmap->GetFormat() == FXDIB_Argb);
   CPDF_Array* pCoords = pDict->GetArray(FX_BSTRC("Coords"));
   if (pCoords == NULL) {
@@ -101,13 +101,13 @@ static void _DrawAxialShading(CFX_DIBitmap* pBitmap,
     }
   }
 }
-static void _DrawRadialShading(CFX_DIBitmap* pBitmap,
-                               CFX_AffineMatrix* pObject2Bitmap,
-                               CPDF_Dictionary* pDict,
-                               CPDF_Function** pFuncs,
-                               int nFuncs,
-                               CPDF_ColorSpace* pCS,
-                               int alpha) {
+static void DrawRadialShading(CFX_DIBitmap* pBitmap,
+                              CFX_AffineMatrix* pObject2Bitmap,
+                              CPDF_Dictionary* pDict,
+                              CPDF_Function** pFuncs,
+                              int nFuncs,
+                              CPDF_ColorSpace* pCS,
+                              int alpha) {
   ASSERT(pBitmap->GetFormat() == FXDIB_Argb);
   CPDF_Array* pCoords = pDict->GetArray(FX_BSTRC("Coords"));
   if (pCoords == NULL) {
@@ -239,13 +239,13 @@ static void _DrawRadialShading(CFX_DIBitmap* pBitmap,
     }
   }
 }
-static void _DrawFuncShading(CFX_DIBitmap* pBitmap,
-                             CFX_AffineMatrix* pObject2Bitmap,
-                             CPDF_Dictionary* pDict,
-                             CPDF_Function** pFuncs,
-                             int nFuncs,
-                             CPDF_ColorSpace* pCS,
-                             int alpha) {
+static void DrawFuncShading(CFX_DIBitmap* pBitmap,
+                            CFX_AffineMatrix* pObject2Bitmap,
+                            CPDF_Dictionary* pDict,
+                            CPDF_Function** pFuncs,
+                            int nFuncs,
+                            CPDF_ColorSpace* pCS,
+                            int alpha) {
   ASSERT(pBitmap->GetFormat() == FXDIB_Argb);
   CPDF_Array* pDomain = pDict->GetArray(FX_BSTRC("Domain"));
   FX_FLOAT xmin = 0, ymin = 0, xmax = 1.0f, ymax = 1.0f;
@@ -323,9 +323,9 @@ FX_BOOL _GetScanlineIntersect(int y,
   x = x1 + FXSYS_MulDiv(x2 - x1, y - y1, y2 - y1);
   return TRUE;
 }
-static void _DrawGouraud(CFX_DIBitmap* pBitmap,
-                         int alpha,
-                         CPDF_MeshVertex triangle[3]) {
+static void DrawGouraud(CFX_DIBitmap* pBitmap,
+                        int alpha,
+                        CPDF_MeshVertex triangle[3]) {
   FX_FLOAT min_y = triangle[0].y, max_y = triangle[0].y;
   for (int i = 1; i < 3; i++) {
     if (min_y > triangle[i].y) {
@@ -408,21 +408,19 @@ static void _DrawGouraud(CFX_DIBitmap* pBitmap,
     }
   }
 }
-static void _DrawFreeGouraudShading(CFX_DIBitmap* pBitmap,
-                                    CFX_AffineMatrix* pObject2Bitmap,
-                                    CPDF_Stream* pShadingStream,
-                                    CPDF_Function** pFuncs,
-                                    int nFuncs,
-                                    CPDF_ColorSpace* pCS,
-                                    int alpha) {
+static void DrawFreeGouraudShading(CFX_DIBitmap* pBitmap,
+                                   CFX_AffineMatrix* pObject2Bitmap,
+                                   CPDF_Stream* pShadingStream,
+                                   CPDF_Function** pFuncs,
+                                   int nFuncs,
+                                   CPDF_ColorSpace* pCS,
+                                   int alpha) {
   ASSERT(pBitmap->GetFormat() == FXDIB_Argb);
-  if (pShadingStream->GetType() != PDFOBJ_STREAM) {
-    return;
-  }
+
   CPDF_MeshStream stream;
-  if (!stream.Load(pShadingStream, pFuncs, nFuncs, pCS)) {
+  if (!stream.Load(pShadingStream, pFuncs, nFuncs, pCS))
     return;
-  }
+
   CPDF_MeshVertex triangle[3];
   FXSYS_memset(triangle, 0, sizeof(triangle));
 
@@ -441,28 +439,26 @@ static void _DrawFreeGouraudShading(CFX_DIBitmap* pBitmap,
       triangle[1] = triangle[2];
       triangle[2] = vertex;
     }
-    _DrawGouraud(pBitmap, alpha, triangle);
+    DrawGouraud(pBitmap, alpha, triangle);
   }
 }
-static void _DrawLatticeGouraudShading(CFX_DIBitmap* pBitmap,
-                                       CFX_AffineMatrix* pObject2Bitmap,
-                                       CPDF_Stream* pShadingStream,
-                                       CPDF_Function** pFuncs,
-                                       int nFuncs,
-                                       CPDF_ColorSpace* pCS,
-                                       int alpha) {
+static void DrawLatticeGouraudShading(CFX_DIBitmap* pBitmap,
+                                      CFX_AffineMatrix* pObject2Bitmap,
+                                      CPDF_Stream* pShadingStream,
+                                      CPDF_Function** pFuncs,
+                                      int nFuncs,
+                                      CPDF_ColorSpace* pCS,
+                                      int alpha) {
   ASSERT(pBitmap->GetFormat() == FXDIB_Argb);
-  if (pShadingStream->GetType() != PDFOBJ_STREAM) {
-    return;
-  }
+
   int row_verts = pShadingStream->GetDict()->GetInteger("VerticesPerRow");
-  if (row_verts < 2) {
+  if (row_verts < 2)
     return;
-  }
+
   CPDF_MeshStream stream;
-  if (!stream.Load(pShadingStream, pFuncs, nFuncs, pCS)) {
+  if (!stream.Load(pShadingStream, pFuncs, nFuncs, pCS))
     return;
-  }
+
   CPDF_MeshVertex* vertex = FX_Alloc2D(CPDF_MeshVertex, row_verts, 2);
   if (!stream.GetVertexRow(vertex, row_verts, pObject2Bitmap)) {
     FX_Free(vertex);
@@ -481,9 +477,9 @@ static void _DrawLatticeGouraudShading(CFX_DIBitmap* pBitmap,
       triangle[0] = last_row[i];
       triangle[1] = this_row[i - 1];
       triangle[2] = last_row[i - 1];
-      _DrawGouraud(pBitmap, alpha, triangle);
+      DrawGouraud(pBitmap, alpha, triangle);
       triangle[2] = this_row[i];
-      _DrawGouraud(pBitmap, alpha, triangle);
+      DrawGouraud(pBitmap, alpha, triangle);
     }
     last_index = 1 - last_index;
   }
@@ -748,29 +744,24 @@ FX_BOOL _CheckCoonTensorPara(const CPDF_MeshStream& stream) {
   return bCoorBits && bCompBits && bFlagBits;
 }
 
-static void _DrawCoonPatchMeshes(FX_BOOL bTensor,
-                                 CFX_DIBitmap* pBitmap,
-                                 CFX_AffineMatrix* pObject2Bitmap,
-                                 CPDF_Stream* pShadingStream,
-                                 CPDF_Function** pFuncs,
-                                 int nFuncs,
-                                 CPDF_ColorSpace* pCS,
-                                 int fill_mode,
-                                 int alpha) {
+static void DrawCoonPatchMeshes(FX_BOOL bTensor,
+                                CFX_DIBitmap* pBitmap,
+                                CFX_AffineMatrix* pObject2Bitmap,
+                                CPDF_Stream* pShadingStream,
+                                CPDF_Function** pFuncs,
+                                int nFuncs,
+                                CPDF_ColorSpace* pCS,
+                                int fill_mode,
+                                int alpha) {
   ASSERT(pBitmap->GetFormat() == FXDIB_Argb);
-  if (pShadingStream->GetType() != PDFOBJ_STREAM) {
-    return;
-  }
+
   CFX_FxgeDevice device;
   device.Attach(pBitmap);
   CPDF_MeshStream stream;
-  if (!stream.Load(pShadingStream, pFuncs, nFuncs, pCS)) {
+  if (!stream.Load(pShadingStream, pFuncs, nFuncs, pCS))
     return;
-  }
-
-  if (!_CheckCoonTensorPara(stream)) {
+  if (!_CheckCoonTensorPara(stream))
     return;
-  }
 
   CPDF_PatchDrawer patch;
   patch.alpha = alpha;
@@ -878,32 +869,32 @@ void CPDF_RenderStatus::DrawShading(CPDF_ShadingPattern* pPattern,
   int fill_mode = m_Options.m_Flags;
   switch (pPattern->m_ShadingType) {
     case 1:
-      _DrawFuncShading(pBitmap, &FinalMatrix, pDict, pFuncs, nFuncs,
-                       pColorSpace, alpha);
+      DrawFuncShading(pBitmap, &FinalMatrix, pDict, pFuncs, nFuncs, pColorSpace,
+                      alpha);
       break;
     case 2:
-      _DrawAxialShading(pBitmap, &FinalMatrix, pDict, pFuncs, nFuncs,
-                        pColorSpace, alpha);
+      DrawAxialShading(pBitmap, &FinalMatrix, pDict, pFuncs, nFuncs,
+                       pColorSpace, alpha);
       break;
     case 3:
-      _DrawRadialShading(pBitmap, &FinalMatrix, pDict, pFuncs, nFuncs,
-                         pColorSpace, alpha);
+      DrawRadialShading(pBitmap, &FinalMatrix, pDict, pFuncs, nFuncs,
+                        pColorSpace, alpha);
       break;
     case 4: {
-      _DrawFreeGouraudShading(pBitmap, &FinalMatrix,
-                              (CPDF_Stream*)pPattern->m_pShadingObj, pFuncs,
-                              nFuncs, pColorSpace, alpha);
+      DrawFreeGouraudShading(pBitmap, &FinalMatrix,
+                             ToStream(pPattern->m_pShadingObj), pFuncs, nFuncs,
+                             pColorSpace, alpha);
     } break;
     case 5: {
-      _DrawLatticeGouraudShading(pBitmap, &FinalMatrix,
-                                 (CPDF_Stream*)pPattern->m_pShadingObj, pFuncs,
-                                 nFuncs, pColorSpace, alpha);
+      DrawLatticeGouraudShading(pBitmap, &FinalMatrix,
+                                ToStream(pPattern->m_pShadingObj), pFuncs,
+                                nFuncs, pColorSpace, alpha);
     } break;
     case 6:
     case 7: {
-      _DrawCoonPatchMeshes(pPattern->m_ShadingType - 6, pBitmap, &FinalMatrix,
-                           (CPDF_Stream*)pPattern->m_pShadingObj, pFuncs,
-                           nFuncs, pColorSpace, fill_mode, alpha);
+      DrawCoonPatchMeshes(pPattern->m_ShadingType - 6, pBitmap, &FinalMatrix,
+                          ToStream(pPattern->m_pShadingObj), pFuncs, nFuncs,
+                          pColorSpace, fill_mode, alpha);
     } break;
   }
   if (bAlphaMode) {
diff --git a/core/src/fpdfapi/fpdf_render/render_int.h b/core/src/fpdfapi/fpdf_render/render_int.h
index 4f86996589..c97cb7105d 100644
--- a/core/src/fpdfapi/fpdf_render/render_int.h
+++ b/core/src/fpdfapi/fpdf_render/render_int.h
@@ -547,7 +547,7 @@ class CPDF_DIBSource : public CFX_DIBSource {
   CPDF_StreamAcc* m_pGlobalStream;
   FX_BOOL m_bStdCS;
   int m_Status;
-  CPDF_Object* m_pMaskStream;
+  CPDF_Stream* m_pMaskStream;
   FX_BOOL m_bHasMask;
 
  private:
diff --git a/core/src/fpdfdoc/doc_annot.cpp b/core/src/fpdfdoc/doc_annot.cpp
index 4d0b703036..d37b1aaadb 100644
--- a/core/src/fpdfdoc/doc_annot.cpp
+++ b/core/src/fpdfdoc/doc_annot.cpp
@@ -187,22 +187,20 @@ CPDF_Stream* FPDFDOC_GetAnnotAP(CPDF_Dictionary* pAnnotDict,
     return NULL;
   }
   const FX_CHAR* ap_entry = "N";
-  if (mode == CPDF_Annot::Down) {
+  if (mode == CPDF_Annot::Down)
     ap_entry = "D";
-  } else if (mode == CPDF_Annot::Rollover) {
+  else if (mode == CPDF_Annot::Rollover)
     ap_entry = "R";
-  }
-  if (!pAP->KeyExist(ap_entry)) {
+  if (!pAP->KeyExist(ap_entry))
     ap_entry = "N";
-  }
+
   CPDF_Object* psub = pAP->GetElementValue(ap_entry);
-  if (psub == NULL) {
-    return NULL;
-  }
-  CPDF_Stream* pStream = NULL;
-  if (psub->GetType() == PDFOBJ_STREAM) {
-    pStream = (CPDF_Stream*)psub;
-  } else if (CPDF_Dictionary* pDict = psub->AsDictionary()) {
+  if (!psub)
+    return nullptr;
+  if (CPDF_Stream* pStream = psub->AsStream())
+    return pStream;
+
+  if (CPDF_Dictionary* pDict = psub->AsDictionary()) {
     CFX_ByteString as = pAnnotDict->GetString("AS");
     if (as.IsEmpty()) {
       CFX_ByteString value = pAnnotDict->GetString(FX_BSTRC("V"));
@@ -210,15 +208,14 @@ CPDF_Stream* FPDFDOC_GetAnnotAP(CPDF_Dictionary* pAnnotDict,
         CPDF_Dictionary* pDict = pAnnotDict->GetDict(FX_BSTRC("Parent"));
         value = pDict ? pDict->GetString(FX_BSTRC("V")) : CFX_ByteString();
       }
-      if (value.IsEmpty() || !pDict->KeyExist(value)) {
+      if (value.IsEmpty() || !pDict->KeyExist(value))
         as = FX_BSTRC("Off");
-      } else {
+      else
         as = value;
-      }
     }
-    pStream = pDict->GetStream(as);
+    return pDict->GetStream(as);
   }
-  return pStream;
+  return nullptr;
 }
 CPDF_Form* CPDF_Annot::GetAPForm(const CPDF_Page* pPage, AppearanceMode mode) {
   CPDF_Stream* pStream = FPDFDOC_GetAnnotAP(m_pAnnotDict, mode);
diff --git a/core/src/fpdfdoc/doc_basic.cpp b/core/src/fpdfdoc/doc_basic.cpp
index b32e34bb4c..414f5749d0 100644
--- a/core/src/fpdfdoc/doc_basic.cpp
+++ b/core/src/fpdfdoc/doc_basic.cpp
@@ -380,15 +380,13 @@ CFX_WideString FILESPEC_EncodeFileName(const CFX_WideStringC& filepath) {
 #endif
 }
 CPDF_Stream* CPDF_FileSpec::GetFileStream() const {
-  if (m_pObj == NULL) {
-    return NULL;
-  }
-  int32_t iType = m_pObj->GetType();
-  if (iType == PDFOBJ_STREAM)
-    return (CPDF_Stream*)m_pObj;
+  if (!m_pObj)
+    return nullptr;
+  if (CPDF_Stream* pStream = m_pObj->AsStream())
+    return pStream;
   if (CPDF_Dictionary* pEF = m_pObj->AsDictionary()->GetDict(FX_BSTRC("EF")))
     return pEF->GetStream(FX_BSTRC("F"));
-  return NULL;
+  return nullptr;
 }
 static void FPDFDOC_FILESPEC_SetFileName(CPDF_Object* pObj,
                                          const CFX_WideStringC& wsFileName,
diff --git a/core/src/fpdfdoc/doc_tagged.cpp b/core/src/fpdfdoc/doc_tagged.cpp
index 2b20e07bb8..f74aa7f6f5 100644
--- a/core/src/fpdfdoc/doc_tagged.cpp
+++ b/core/src/fpdfdoc/doc_tagged.cpp
@@ -317,8 +317,8 @@ static CPDF_Dictionary* FindAttrDict(CPDF_Object* pAttrs,
   CPDF_Dictionary* pDict = nullptr;
   if (pAttrs->IsDictionary()) {
     pDict = pAttrs->AsDictionary();
-  } else if (pAttrs->GetType() == PDFOBJ_STREAM) {
-    pDict = ((CPDF_Stream*)pAttrs)->GetDict();
+  } else if (CPDF_Stream* pStream = pAttrs->AsStream()) {
+    pDict = pStream->GetDict();
   } else if (CPDF_Array* pArray = pAttrs->AsArray()) {
     for (FX_DWORD i = 0; i < pArray->GetCount(); i++) {
       CPDF_Object* pElement = pArray->GetElementValue(i);
@@ -327,10 +327,9 @@ static CPDF_Dictionary* FindAttrDict(CPDF_Object* pAttrs,
         return pDict;
     }
   }
-  if (pDict && pDict->GetString(FX_BSTRC("O")) == owner) {
+  if (pDict && pDict->GetString(FX_BSTRC("O")) == owner)
     return pDict;
-  }
-  return NULL;
+  return nullptr;
 }
 CPDF_Object* CPDF_StructElementImpl::GetAttr(const CFX_ByteStringC& owner,
                                              const CFX_ByteStringC& name,
diff --git a/fpdfsdk/src/fpdf_flatten.cpp b/fpdfsdk/src/fpdf_flatten.cpp
index f4d49ce182..39441c4aef 100644
--- a/fpdfsdk/src/fpdf_flatten.cpp
+++ b/fpdfsdk/src/fpdf_flatten.cpp
@@ -211,7 +211,7 @@ void SetPageContents(CFX_ByteString key,
   switch (iType) {
     case PDFOBJ_STREAM: {
       pContentsArray = new CPDF_Array;
-      CPDF_Stream* pContents = (CPDF_Stream*)pContentsObj;
+      CPDF_Stream* pContents = pContentsObj->AsStream();
       FX_DWORD dwObjNum = pDocument->AddIndirectObject(pContents);
       CPDF_StreamAcc acc;
       acc.LoadAllData(pContents);
@@ -447,15 +447,14 @@ DLLEXPORT int STDCALL FPDFPage_Flatten(FPDF_PAGE page, int nFlag) {
             if (pFirstObj->GetType() == PDFOBJ_REFERENCE)
               pFirstObj = pFirstObj->GetDirect();
 
-            if (pFirstObj->GetType() != PDFOBJ_STREAM)
+            if (!pFirstObj->IsStream())
               continue;
 
-            pAPStream = (CPDF_Stream*)pFirstObj;
+            pAPStream = pFirstObj->AsStream();
           }
         }
       }
     }
-
     if (!pAPStream)
       continue;
 
diff --git a/fpdfsdk/src/fpdf_transformpage.cpp b/fpdfsdk/src/fpdf_transformpage.cpp
index d2ad26bf64..20713fe07d 100644
--- a/fpdfsdk/src/fpdf_transformpage.cpp
+++ b/fpdfsdk/src/fpdf_transformpage.cpp
@@ -144,7 +144,7 @@ DLLEXPORT FPDF_BOOL STDCALL FPDFPage_TransFormWithClip(FPDF_PAGE page,
         CPDF_Reference* pRef = new CPDF_Reference(pDoc, pStream->GetObjNum());
         pContentArray->InsertAt(0, pRef);
         pContentArray->AddReference(pDoc, pEndStream);
-      } else if (pDirectObj->GetType() == PDFOBJ_STREAM) {
+      } else if (pDirectObj->IsStream()) {
         pContentArray = new CPDF_Array();
         pContentArray->AddReference(pDoc, pStream->GetObjNum());
         pContentArray->AddReference(pDoc, pDirectObj->GetObjNum());
@@ -162,16 +162,17 @@ DLLEXPORT FPDF_BOOL STDCALL FPDFPage_TransFormWithClip(FPDF_PAGE page,
     if (pPattenDict) {
       FX_POSITION pos = pPattenDict->GetStartPos();
       while (pos) {
-        CPDF_Dictionary* pDict = NULL;
+        CPDF_Dictionary* pDict = nullptr;
         CFX_ByteString key;
         CPDF_Object* pObj = pPattenDict->GetNextElement(pos, key);
         if (pObj->GetType() == PDFOBJ_REFERENCE)
           pObj = pObj->GetDirect();
-        if (pObj->IsDictionary()) {
+
+        if (pObj->IsDictionary())
           pDict = pObj->AsDictionary();
-        } else if (pObj->GetType() == PDFOBJ_STREAM) {
-          pDict = ((CPDF_Stream*)pObj)->GetDict();
-        } else
+        else if (CPDF_Stream* pStream = pObj->AsStream())
+          pDict = pStream->GetDict();
+        else
           continue;
 
         CFX_AffineMatrix m = pDict->GetMatrix(FX_BSTRC("Matrix"));
@@ -313,7 +314,7 @@ DLLEXPORT void STDCALL FPDFPage_InsertClipPath(FPDF_PAGE page,
         pContentArray = pArray;
         CPDF_Reference* pRef = new CPDF_Reference(pDoc, pStream->GetObjNum());
         pContentArray->InsertAt(0, pRef);
-      } else if (pDirectObj->GetType() == PDFOBJ_STREAM) {
+      } else if (pDirectObj->IsStream()) {
         pContentArray = new CPDF_Array();
         pContentArray->AddReference(pDoc, pStream->GetObjNum());
         pContentArray->AddReference(pDoc, pDirectObj->GetObjNum());
diff --git a/fpdfsdk/src/fpdfppo.cpp b/fpdfsdk/src/fpdfppo.cpp
index 7b589b585f..c9df813789 100644
--- a/fpdfsdk/src/fpdfppo.cpp
+++ b/fpdfsdk/src/fpdfppo.cpp
@@ -247,7 +247,7 @@ FX_BOOL CPDF_PageOrganizer::UpdateReference(CPDF_Object* pObj,
       break;
     }
     case PDFOBJ_STREAM: {
-      CPDF_Stream* pStream = (CPDF_Stream*)pObj;
+      CPDF_Stream* pStream = pObj->AsStream();
       CPDF_Dictionary* pDict = pStream->GetDict();
       if (pDict) {
         if (!UpdateReference(pDict, pDoc, pObjNumberMap))
diff --git a/fpdfsdk/src/fsdk_baseform.cpp b/fpdfsdk/src/fsdk_baseform.cpp
index 3b845b017e..e083220fe2 100644
--- a/fpdfsdk/src/fsdk_baseform.cpp
+++ b/fpdfsdk/src/fsdk_baseform.cpp
@@ -62,7 +62,7 @@ FX_BOOL CPDFSDK_Widget::IsWidgetAppearanceValid(
     case FIELDTYPE_LISTBOX:
     case FIELDTYPE_TEXTFIELD:
     case FIELDTYPE_SIGNATURE:
-      return psub->GetType() == PDFOBJ_STREAM;
+      return psub->IsStream();
     case FIELDTYPE_CHECKBOX:
     case FIELDTYPE_RADIOBUTTON:
       if (CPDF_Dictionary* pSubDict = psub->AsDictionary()) {